Tire having a carcass ply turn-up portion with a concave segment
A tire having a section height, a maximum section width, an upper section above the maximum section width, and a lower section below the maximum section width is provided. The tire includes a circumferential tread, a pair of sidewalls, a pair of bead regions each having a bead core, and at least one carcass ply extending circumferentially about the tire from one bead region to the other. The at least one carcass ply is wound outwardly about at least one of the bead cores and extends toward the tread to form a turn-up portion that terminates at a turn-up end. The turn-up portion includes a concave segment that begins in the bead region and ends short of the turn-up end or at the turn-up end.
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This application is a continuation of U.S. Application No. 11/496,611 filed on Jul. 31, 2006, the disclosure of which is incorporated by reference herein in its entirety.
FIELD OF THE INVENTIONThe present application relates to tires and, more particularly, to a tire having a carcass ply turn-up portion with a concave segment to improve lower sidewall performance of the tire.
BACKGROUNDIn an inflated and loaded condition, a radial tire is subject to bending moments at the lower sidewall areas at the center of the tire footprint. The strains and stresses created by the moments are directly related to the lower sidewall performance of the tire.
Previous research and studies have demonstrated that increasing lower sidewall stiffness can reduce tire deformation in the region and improve lower sidewall performance. Because of the interaction between the wheel flange and tire contour in its mounting region, the lower sidewall of a rolling tire experiences high stress and strain cycles. Many engineering techniques and design methods have been developed to reduce stress and strain in the region.
SUMMARYIn one embodiment, a tire having a section height, a maximum section width, an upper section above the maximum section width, and a lower section below the maximum section width is provided. The tire includes a circumferential tread, a pair of sidewalls, a pair of bead regions each having a bead core, and at least one carcass ply extending circumferentially about the tire from one bead portion to the other. The at least one carcass ply is wound outwardly about at least one of the bead cores and extends toward the tread to form a turn-up portion that terminates at a turn-up end. In this embodiment, the turn-up portion has a height that is less than about 50% of the section height of the tire and includes a concave segment that extends from the bead region to the turn-up end.
In another embodiment, a tire having a section height is provided. The tire includes a circumferential tread, a pair of sidewalls, a pair of bead portions each having a bead core, and at least one carcass ply extending circumferentially about the tire from one bead portion to the other. The at least one carcass ply is wound outwardly about at least one of the bead cores and extends toward the tread to form a turn-up portion that terminates at a turn-up end. In this embodiment, a section of the turn-up portion follows a concave path that begins at a height of about 10 mm to about 20 mm and terminates at a height that is between about 20% to about 50% of the section height of the tire, wherein the heights are measured from the base of the bead core.
The accompanying drawings, together with the detailed description provided below, describe exemplary embodiments of the claimed invention. In the drawings and description that follow, like elements are identified with the same reference numerals. The drawings are not to scale and the proportion of certain elements may be exaggerated for the purpose of illustration.
The following includes definitions of selected terms employed herein. The definitions include various examples and/or forms of components that fall within the scope of a term. The examples are not intended to be limiting.
“Axial” or “axially” refer to a direction that is parallel to the axis of rotation of a tire.
“Circumferential” and “circumferentially” refer to a direction extending along the perimeter of the surface of the tread parallel to the equatorial plane perpendicular to the axial direction of the tire.
“Equatorial plane” refers to the plane that is perpendicular to the tire's axis of rotation and passes through the center of the tire's tread.
“Groove” refers to an elongated void in the tread of the tire that extends circumferentially in a straight, curved or zig-zag manner.
“Lateral” or “laterally” refer to a direction along the tread of the tire going from one sidewall of the tire to the other sidewall.
“Radial” or “radially” refer to a direction perpendicular to the axis of rotation of the tire.
“Sidewall” refers to that portion of the tire between the tread and the bead.
“Tread” refers to that portion of the tire that comes into contact with a surface under normal load.
Directions are also stated in this application with reference to the axis of rotation of the tire. The terms “upward” and “upwardly” refer to a general direction towards the tread of the tire, whereas “downward” and “downwardly” refer to the general direction towards the axis of rotation of the tire. Thus, when relative directional terms such as “upper” and “lower” are used in connection with an element, the “upper” element is spaced closer to the tread than the “lower” element. Additionally, when relative directional terms such as “above” or “below” are used in connection with an element, an element that is “above” another element is closer to the tread than the other element. The terms “inward” and “inwardly” refer to a general direction towards the equatorial plane of the tire, whereas “outward” and “outwardly” refer to a general direction away from the equatorial plane of the tire and towards the sidewall of the tire. Thus, when relative directional terms such as “inner” and “outer” are used in connection with an element, the “inner” element is spaced closer to the equatorial plane of the tire than the “outer” element.
Illustrated in
With continued reference to
The tire 100 further includes first and second carcass plies 114, 116 that extend circumferentially about the tire 100 from one bead region (e.g., bead region 106) to the other bead region (not shown). The first and second carcass plies 114, 116 are wound outwardly about the bead core 108 and extend upwardly towards the tread 102 to form first and second turn-up portions 118, 120, respectively, which will be discussed in further detail below. Each turn-up portion 118, 120 terminates at a turn-up end 122, 124, respectively. Although the tire 100 illustrated in
In one embodiment, the first and second carcass plies 114, 116 include parallel-aligned cords that are radially disposed. In other words, the parallel-aligned cords are oriented substantially perpendicular to the equatorial plane Ep of the tire 100. In alternative embodiments, one or more of the carcass plies can include parallel-aligned cords that are biased with respect to the equatorial plane Ep of the tire 100. In all cases, the cords can be constructed of, for example, nylon or polyester or rayon.
With continued reference to
In one embodiment, the first and second belts 126, 128 include parallel-aligned cords or wires that are radially disposed. In alternative embodiments, one or more of the belts can include parallel-aligned cords or wires that are biased with respect to the equatorial plane Ep of the tire 100. In all cases, the cords or wires can be constructed of, for example, steel or other steel alloys.
With continued reference to
The tire 100 further includes a tread cap 142 provided between the tread 102 and the first and second belts 126, 128. The tread cap 142 can be used to assist in holding the components of the tire together (e.g., the belts, plies, and tread). The tread cap 142 can include, for example, one or more polyester or nylon fabric plies. Although shown in the
With continued reference to the embodiment illustrated in
In one embodiment, the height H1 of the first turn-up portion 118 is less than about 50% of the section height H0 of the tire 100 (which is measured from the outer tread surface at the equatorial plane Ep to the base of the bead core 108). In another embodiment, the height H1 of the first turn-up portion 118 is between about 25% and about 50% of the section height H0 of the tire 100. Preferably, the height H1 of the first turn-up portion 118 is between about 40% and about 50% of the section height H0 of the tire 100.
In one embodiment, the height H2 of the second turn-up portion 120 can be less than about 35% of the section height H0 of the tire 100. Preferably, the height H2 of the second turn-up portion 120 is between about 10% and about 35% of the section height H0 of the tire 100.
In the illustrated embodiment, the first turn-up portion 118 of the second carcass ply 114 includes a concave section or segment 144 that follows a concave path (hereinafter referred to as “concave segment 144”). For illustration purposes, the concave segment 144 of the turn-up portion 118 is hatched in order to differentiate it from the rest of the turn-up portion 118.
Illustrated in
The beginning and end of the concave segment 144 can also be discussed in terms of height relative to the base of the bead core 108. In one embodiment, the concave segment 144 of the first turn-up portion 118 can begin in the bead region 106 (e.g., at a height H3 of about 10 mm to about 20 mm, preferably 15 mm) and terminate at a height (e.g., H4) of between about 20% and about 50% of the section height H0 of the tire 100. In another embodiment, the concave segment 144 can terminate at a height H4 of between about 20% and 35% of the section height H0 of the tire 100.
As shown in
To force the concave segment 144 to follow the continuous concave path, the tire 100 can be constructed in at least three configurations.
In one configuration, the tire can include an insert that is structured and arranged to assist, at least in part, in forming the concave segment 144 of the first turn-up portion 118. Illustrated in
With reference to
In the illustrated embodiment, the insert 302 is positioned between the first turn-up portion 118 of the first carcass ply 114 and the sidewall 104 of the tire 300. In an embodiment where the tire 300 includes only one carcass ply (not shown), the insert 302 is provided between such carcass ply and the sidewall 104 of the tire 300.
As shown in
Similarly, the upper end 304 of the insert 302 extends above the first turn-up end 122 of the first turn-up portion 118. Preferably, the upper end 304 of the insert 302 extends above the first turn-up end 122 of the first turn-up portion 118 a radial distance D2 between about 6 mm and about 24 mm.
The insert 302 can be constructed from a variety of materials including, without limitation, an elastomeric material (e.g., rubber). In one embodiment, the insert 302 is constructed from an elastomeric material having a higher modulus of elasticity than the material from which the sidewall 104 is constructed.
The insert 302 described above and illustrated in
In a second configuration (not shown), the insert 302 described above and illustrated in
In a third configuration, the tire can include a reinforcement ply that is structured and arranged to assist, at least in part, in forming the concave segment 144 of the first turn-up portion 118. Illustrated in
The reinforcement ply 402 extends circumferentially about the tire 400 and is provided between the first turn-up portion 118 and the sidewall 104 of the tire 400. In an embodiment where the tire 400 includes only one carcass ply (not shown), the reinforcement ply 402 is provided between the single carcass ply and the sidewall 104 of the tire 400.
As shown in
With reference to
In the illustrated embodiment, the lower edge 406 of the reinforcement ply 402 is folded up towards the tread 102 of the tire 400, thereby forming a fold-up portion 408 and a crease 410. The fold-up portion 408 cooperates with the adjacent portion of the reinforcement ply 402 from which it overlaps to form a dual layer reinforcement. Preferably, the radial distance D4 between the crease 410 and the end of the fold-up portion 408 of the reinforcement ply 402 (i.e., the lower edge 406) is between about 6 mm and about 24 mm. The extent of the fold can also be discussed in relation to fold percentage (i.e., the relationship between the length of the fold-up portion 408 of the reinforcement ply 402 and the length of the remaining portion of the reinforcement ply 402 defined between the crease 410 and the upper edge 404 of the reinforcement ply 402). Preferably, the fold-up portion 408 can have a fold percentage between about 25% and about 50%. In another embodiment (not shown), the folded reinforcement ply 402 can be replaced with two or more separate pieces of ply material cut to different lengths.
With continued reference to
Additionally, the lower edge 406 of the reinforcement ply 402 extends above the second turn-up end 124 of the second turn-up portion 120. Preferably, the lower edge 406 of the reinforcement ply 402 extends beyond the second turn-up end 124 of the second turn-up portion 120 a radial distance D6 between about 6 mm and about 12 mm.
The reinforcement ply 402 is constructed of a set of parallel-aligned cords encapsulated in rubber or another elastomeric material. In one embodiment, the set of parallel-aligned cords are radially disposed. In other words, the parallel-aligned cords are oriented substantially perpendicular to the equatorial plane Ep of the tire 400. In alternative embodiments, the reinforcement ply 402 can include parallel-aligned cords that are biased with respect to the equatorial plane Ep of the tire 400. In all cases, the cords can be constructed of, for example, nylon or polyester.
In one embodiment, the reinforcement ply 402 has a thickness between about 0.5 mm and about 1.0 mm. Preferably, the reinforcement ply 402 has a thickness of about 0.9 mm.
The reinforcement ply 402 described above and illustrated in
By providing a tire that includes a carcass ply turn-up portion having a concave segment similar to the one discussed above, sidewall performance of the tire can be improved. Specifically, the existence of the concave segment in the carcass ply turn-up portion can reduce lower sidewall strain energy density. Reduction of strain energy density in the lower sidewall region of the tire can lead to an improvement in durability (e.g., a reduction of possible separation between the sidewall and the bodyply of the tire), a reduction of deflection of the sidewall, and/or an improvement in vehicle handling.
To the extent that the term “includes” or “including” is used in the specification or the claims, it is intended to be inclusive in a manner similar to the term “comprising” as that term is interpreted when employed as a transitional word in a claim. Furthermore, to the extent that the term “or” is employed (e.g., A or B) it is intended to mean “A or B or both.” When the applicants intend to indicate “only A or B but not both” then the term “only A or B but not both” is employed. Thus, use of the term “or” herein is the inclusive, and not the exclusive use. See, Bryan A. Garner, A Dictionary of Modern Legal Usage 624 (2d. Ed. 1995). Also, to the extent that the terms “in” or “into” are used in the specification or the claims, it is intended to additionally mean “on” or “onto.”
While the present application illustrates various embodiments, and while these embodiments have been described in some detail, it is not the intention of the applicant to restrict or in any way limit the scope of the claimed invention to such detail. Departures may be made from such details without departing from the spirit or scope of the applicant's claimed invention. Therefore, the invention, in its broader aspects, is not limited to the specific details, the representative apparatus, and illustrative examples shown and described.
Claims
1. A tire having a section height, a maximum section width, an upper section above the maximum section width, and a lower section below the maximum section width, the tire comprising:
- a circumferential tread;
- a pair of sidewalls;
- a pair of bead regions, each having a bead core;
- at least one carcass ply extending circumferentially about the tire from one bead region to the other, wherein the at least one carcass ply is wound outwardly about at least one of the bead cores to form a turn-up portion that terminates at a turn-up end, wherein the turn-up portion includes an outward facing concave segment that begins in the bead region and ends at a height that is between about 20% to about 50% of the section height of the tire; and
- a solid elastomeric insert provided between the turn-up portion and one of the sidewalls of the tire, wherein the solid elastomeric insert has a lower end positioned at a radial height above the bead core, extends upward above the turn-up portion, terminates at an upper end in the upper section of the tire, and extends circumferentially about the tire, and wherein the solid elastomeric insert assists in forming the outward facing concave segment of the turn-up portion.
2. The tire of claim 1 wherein the outward facing concave segment of the turn-up portion has a single radius between about 380 mm to about 1500 mm.
3. The tire of claim 1, further comprising a second carcass ply wound outwardly about at least one of the bead cores to form a second turn-up portion that terminates at a second turn-up end, wherein the second turn-up portion has a height that is less than about 35% of the section height of the tire.
4. The tire of claim 1, wherein the outward facing concave segment of the turn-up portion is defined by two or more radii between about 380 mm to about 1500 mm with tangents that form a continuous surface.
5. The tire of claim 1, wherein the sidewalls are constructed of a first elastomeric material and the insert is constructed of a second elastomeric material that has a higher modulus of elasticity than the first elastomeric material.
6. The tire of claim 1, further including a second elastomeric insert provided between a turn-up portion and a second sidewall of the tire, wherein the second elastomeric insert assists in forming the outward facing concave segment of the turn-up portion of the second sidewall and wherein the second elastomeric insert extends circumferentially about the tire.
7. A tire having a section height, a maximum section width, an upper section above the maximum section width, and a lower section below the maximum section width, the tire comprising:
- a circumferential tread;
- a pair of sidewalls;
- a pair of bead regions, each having a bead core;
- at least a pair of carcass plies extending circumferentially about the tire from one bead region to the other, including at least a first carcass ply disposed and a second carcass ply, wherein each of the first and second carcass plies is wound outwardly about each bead core to form first and second turn-up portions that terminate at first and second turn-up ends, wherein the first turn-up portions are disposed between one of the bead regions and the sidewall and the second turn-up portions are disposed between the one of the bead regions and the first turn-up portion, wherein the first turn-up portions include an outward facing concave segment that begin in the bead regions and end at a first height that is between about 20% to about 50% of the section height of the tire, and wherein the second turn-up portions end at a second height that is less than the first height; and
- a means for forcing at least one of the sections of at least one of the turn-up portions to follow the outward facing concave path, the means having a lower end positioned at a radial height above the bead core and an upper end located in the upper section of the tire.
8. The tire of claim 7, wherein the means for forcing at least one of the sections of at least one of the turn-up portions to follow the outward facing concave path is at least one solid elastomeric insert that extends circumferentially about the tire, wherein the at least one solid elastomeric insert is provided between one of the turn-up portions and one of the sidewalls of the tire.
9. The tire of claim 7 wherein the outward facing concave segment of the turn-up portion has a single radius between about 380 mm to about 1500 mm.
10. The tire of claim 7 wherein the outward facing concave segment of the turn-up portion has a single radius between about 800 mm and about 1000 mm.
11. The tire of claim 7 wherein the outward facing concave segment of the turn-up portion begins at a height of about 10 mm to about 20 mm, measured from a base of the bead core.
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Type: Grant
Filed: Oct 29, 2008
Date of Patent: Feb 21, 2012
Patent Publication Number: 20090044894
Assignee: Bridgestone Americas Tire Operations, LLC (Nashville, TN)
Inventors: Jie Jin (Copley, OH), Richard Wright (Wadsworth, OH)
Primary Examiner: Justin Fischer
Application Number: 12/260,547
International Classification: B60C 15/00 (20060101); B60C 15/06 (20060101);